Mandrel



Feb. 16,1926. 1,513,386

M. F; FIELD Filed July 21, 1921 atto: ne q product.

Patented Feb. 16, 1926.l

unirse stares MALETIS rLoYD rrELn, or

AKRON, OHIO, ASSIG'NOR TO HIIVISELF AND ALPHONSO H. MARIETTA, OF AKRON, OHIO.

MANDREL.

Application lcd July 21, 1921. Serial No. 486,415.

` To all whom it may concern Be itknown that I, MALnTIs FLOYD FIELD, av` citizen of the United States, residing' at Akron, of Ohio, have invented new and useful Improvements in Mandrels, of which the following is a specification. i

This invention relates to certain new and useful improvementsin mandrels and particularly to a mandrel adapted for use in the manufacture of tubular articles of rubber or like material, such as inner tubes for pneumatic tires.

In the ordinary method of mamifacturing such tubes, a cylindrical mandrel is covered with unvu'lcanized rubber and the rubber covered mandrel is wrapped with fabric or placed within a retainingmold to hold the rubber close against the mandrel during' vulcanization.

It is an object of the invention to provide a less expensive, more rapid method of manufacturing such `tubes which when followed will provide. a high grade, compact, uniform It isa further object of the invention to provide a mandrel'of simple, inexpensive construction which may be used without wrapping or other restraining means and to 'thus provide means whereby a strong, durable tube which may be constructed at a low cost.

A specific object is to provide a hollow formhaving an enclosed cavity with openings leading therefrom to the outer face thereof and to provide means whereby the air may be excluded therefrom and a vaclum or partial vacuum formed therein so that rubber placed thereon will be held closely to the form during vulcanization.

An additional object is to provide a new and improved tube for pneumatic tires.

lIhe above and additional objects are accomplished by the novel construct-ion, combination and arrangement of parts and manner of using such parts hereinafter disclosed and illustrated in the accompanying' drawing, wherein I have shown a preferred embodiment of the invention, it beingunderstood that the invention is capable of various adaptationsand that changes and modifications may be made or substitutions resorted to which come within the scope of the claims hereunto appended.

In the drawings in which similar numerin the county of Summit and State y als of reference have been employed to designate the same or similar parts they appear .in the several views Figurel is a perspective view of a mandrel constructed in accordance with this invention.

Figure Q is a longitudinal view showing my improved mandrel in central, longitudinal section with parts removed, and also showing a covering of rubber as the same is placed thereon in the manufacture of a rubber tube.

Figure 3 is a fragmentary view showing in longitudinal, cent-ral section another adaptation of my improved mandrel.

Figure at is a fragmentary view showing in side elevation a portion of a tube manufactured by my improved process.

Proceeding now to a detailed description of the invention, with reference to the accom ianying' drawing', the numeral 5 denotes a hollow, cylindrical member or tube preferably composed of metal or other rigid material. The tube 5 is internally threaded at each end thereof and an exteriorly threaded plug 6 is operatively secured in one end thereof. The numeral 6" denotes an annular flange which is provided with a flat face G arranged thereon so as to contact with thc end of the tube 5 when the plug is secured therein. The numeral 7 denotes a plug' which is similar to the plug 6 and is simi larly threaded in the other end of the tube 5. An annular flange 7 is provided on the plug 7 so as to present a fiat face 7" at the end of the tube 5. The plug 7 is also provided with an interiorly threaded axial bore S into which is threaded an outwardly projecting pipe 9. The pipe 9 is provided with a. suitable valve 10 for a purpose to be hereinafter described. A plurality of b ores or openings 11 are formed in the wall of the tube 5 so as to extend therethrough. The numeral 12 denotes a wire which is closely wound upon the tube 5 so as to cover the en tire outer surface thereof. Each end of the wire 12 is brazed, soldered or otherwise secured to the tube 5 so that said wire becomes a permanent part thereof. The annular flanges in the plugs 6 and 7 are of substantially the same diameter as the wire wound mandrel 5 so that a form of even diameter is provided.

In the adaptation of the invention shown in Figure 3, woven fabric 1G or other reticulated or porous material is provided instead Y nire. i is/then subjectet to a vuleanizmg heat or the of the wire 12.

To construct a rubber tube on my improved device,rthe wire-wound surface is completely covered with a sheet of unvulcanizedY rubber.v The tube 9 is operatively connected to a pump or similar device, the 'alve 10 is opened and the air within the cavity 141 is pumped therefrom so as to form a vacuum or partial vacuum therein. The wire 1Q, being round in cross section, a space is provided Abetween the wire 'covering and the mandrel. The Yopenings 11 communicate with this space and the air is drawn from the space between the convolutiens of the wire 12, thus causing a vaeuum or partial vacuum to exist between the layer 13 of rubber and the tube 5. When the .desired amount of air has been thus excluded from the mandrel the valve 10 is operated to'close Vthe tube 9v and the layer 13 is thus closely y held about the mandrel by atmospheric presne .mandrel with the layer 18 thereon layer 13 is Votherwise cured. 1o remove the tube which is thus formed, the valve 10 is op erated to open the pipe and air under pressure is forced therein. The airY thus forced into the mandrel will iiow between the convolutions of the wire 12 and the 'tube 13 will tially extending series of laterally directed grooves 15 of semi-circular cross section and a serrated surface is thus provided which will prevent a longitudinal slipping of the tube in a pneumatic tire casing.

lt will thus be seen that I have provided a mandrel of simple, inexpensive construction which is capable of modification to provide a form for the construction of various articles, and which when used willA produce a compact, uniform product at a compai tively low cost. i Y

Having thus described my invention in detail and illustrated one'embodiment thereof, what l claim as new and desire to secure by Letters-Patent is:-

1. ln a mandrel for manufacturing inner tubes, a hollow cylinder form; an opening in the wall thereof and 4a covering arranged thereon and forming a part thereof, said covering comprising a flexible member wound spirally around the tube. Y p

2. ln a device of the class described, a -hollow elongated form, a layer lof wire wound thereon, openings in the wall of said ferm underneath the said layer, and means whereby air may be drawn from the cavity in the form. l

Z3. In a device lof the class described, a hollow cylindrical form closed at both ends, a layerof wire wound thereon, openings in the wall of the form at points underlying said layer of wire, and a valve controlled opening leading from the interior of the form.

1n testimony whereof I have hereunto set my hand.

MALETS FLOYD FIELD, 

